Thanks for your comment. I guess sometimes pouncing is not needed but if you look at flights like LHR - MLE - LHR these flights in J are always gone by one minute past midnight and work out much less expensive than the full fare equivalent and certainly much less expensive than the fully flexible fare which an avios reward flight is (apart for the £35 cancellation fee)

If you can get the Avios flight your want at anytime that's great. If I know 355 days in advance the BA flight I need I will continue the midnight vigil. I know the Qatar flights I want, I will book them when they become available, why wait if you know what you want.

Thanks to all for your help, I will continue to monitor.